Self-supporting clamp



C. C. ROBERTS. SELF SUPPORTING GLAMP. APPLICATION FILED opr. 21, 1919.

Patented June 20, 1922.

\ lNl/EA/TOR Charles G Hoberis Arm/my CHARLES C. ROBERTS, E ANSONIA, GGNNECTIGUI.

snLr-surron'rine orient."

Specification of Letters Patent Patented June 230, 1922.

Application filed October 21, 1919. Serial No. 332,331.

To all whom it may concern Be it known that i, Crrsinnns C. ltonenrs, a citizen. of the United t lcates, residing at Ansonia, inthe county of New Haven and the State of Connecticut have invented a certain new and useful lillpit).KEiltlltlil h cl i- Fiupport-ing Clamps, of which the following is a specification.

My invention relates to devices for holding work inplace on machine heds, particularly in machines wherein the work is operated upon by cutting tools, such lath'es, planers, shapers and the like, and its particular object is to provide a device of this character in which a work-holding strap is 'lulcrunied on and adjustably connected to a support. adapted to rest on the machine bed.

Another object of the invention is the provision of a device of the above described character which includes a positive means for adjustably locking a strap to a post.

With these and other objects in view my invention consists in the details of construction and manner of operation set forth in the following description and accompanyiIlg drawings in which like reference charters refer to corresponding parts.

In the accompanying drawing forming a part of this specification, and in which similar reference characters designate corresponding parts throughout the several views:

Figure 1 is a top view of my device, portions thereof being shown broken away;

Figure .2, a longitudinal sectional view taken on. linen-4; in Figure 1 Figure 3, an end view of the strap head with the bars removed therefrom, and

Figure 4:, a fragmentary portion of a modification.

Referring to Figures 1 to 3 inclusive. the strap comprises the bars 2, 2 and the head 3. The rearward extremities of the bars 2, 2 are provided with vertical apertures 4C, 4: for the reception of pins 5, 5 hy' means of which latter the he rs are secured to and joinnaled to swing in the passages ("3. 6 in the head. These passages G. b preferably have their side walls '7, T. inclined outwardly and rearwardly to provide the necessary clearance to enable the to spread or swing to and from each other. By providing a series of apertures a, 41 in the rearward extremity of each bar the distance between the head 3 of the strap and the forward ends 8. 8 of the bars is made adjustable, since the bearing pins 5, 5 may be passed through any oppos1te pair of apertures. The forward ends 8 8 of the bars rest on the work 9. while the rear ends are pivoted in the head 3 which is supported on the post 10.

When a pair of bars are employed as shown, the head 3 is provided with a vertical passage 11 between the bars for the passage of the supporting post 10. Thispost is secured. to the head in any desired manner but for the purpose of illustration I have shown its front face provided with teeth 12 which interlock with corresponding teeth 13 in the front wall of the passage 11. These teeth are preferably provided with horizontal faces in orderto facilitate the interlocking action when the device is under stress, that is, the upper faces of the teeth on the post and the lower faces of the teeth in the wall of the passage are in a plane at right angles to the axis of the post, so that when the teeth are interlocked and the device is under stress there will be no tendency of the faces of the teeth to thrust the post forwardly or rearwardly and upset the. strap. The passage 11 in the head 3 is longer than the thickness of the post, thereby per mitting sufficient movement. of the post within the passage to unlock the teeth.

In order to positively lock the head- 3 in engagement with the post- 10. a wedge 14 is provided for insertion in the passage 11 intermediate the rear wall 15 of the head 8, and the rear of the post 10. The rear wall 15 is tapered inwardly of the passage 11 and toward the bottom of the head 3. The wedge 1a is also tapered. and adapted to have its smaller end 14 first inserted in the passage 11 in order to provide that bending and wedging action necessary to clamp the head 3 to post 10. The wedge 14 is provided with a recess 16 the bottom face 16 of which recess is tapered parallel with the tapered side of the wedge: and which recess cooperates with a'lug 17 formed upon the wall 15 to prevent the entire disconnection of the wedge 1 from the device, such as is apt to occur during transportation of the device. A turn button 18 is preferably mounted upon the top of the head. 3, and adapted for cam action upon the wedge .14, to prevent disconnection of the same when in locked position. The lower extremity of the post 10 is in the form of a. ball 19 which rests in the socket 20 in the base 21 forming a swivel joint. This swivel joint permits the post- 10 to be tipped forwardly or rearwardly so that the forward ends 8, 8 of the bars 2, 2 can rest flat upon the work even though the surface of the work, where the bars rest, is not horizontal.

Bridging the bars 2, 2 is a plate 22 through which passes the draw bolt 23, the head 24. of which latter bears against the under side of the machine bed 25. The plate 22 is sufficiently wide to permit a maximum separation or spreading apart of the bars 2, 2 for adjustment purposes and is provided with a pair of retaining bands 80 which pass around under the bars to hold the plate in place when the device is not in use.

From the above description it will be apparent that when the strap is adjusted and leveled to the work so that the forward ends,

8,8 of the bars 2, 2 bear on the work 9, the

latter can be securely gripped between the bars and the machine bed by turning the nut 26 on the draw bolt 23. The distinguishing feature of my device, however, is the fact that the strap, which in the present instance comprehends both the bars 2, 2 and the head 3, carries its own post or support, so that when the device is not in use the parts are all connected together. In the present style of straps the supporting posts are either separate and disconnected from the straps or no post is used at all, a series of filling in blocks being utilized as a fulcrum point.

Having all the parts connected together enables one to pick up the entire device without accidentally losing any of the parts or the inconvenience of finding the separate parts and assembling them together when the work is clamped down. It should be noticed also post 10 is adjustably secured in a vertical passage in the head 27 in the same manner as 'shown in Figures 1 and 2.

Attention is called to the fact that when assembled the clamping strap and supporting post form a rigid elbow having arms at right angles to each other, the clamping strap representing the horizontal arm and the supporting post the vertical arm. The

' device as a whole is fulcrumed on the lower end of the vertical arm or post 10 by means of the swivel joint in the present case. This permits a wider range of adjustment than in the old form where the clamping strap is supported on wooden packing blocks.

In operation, the device is positioned with the base 21 upon the machine bed 25, adjacent the work 9 to be clamped to the machine bed, and the straps 2, 2 are adjusted upon the post 10 by releasing the wedge 14. until the free ends 8 thereof engage the work 9 substantially as illustrated in Figure 2 of the drawing. After the clamping strap is thus levelled on the work, the clamp or wedge 14 is properly inserted in the passage 11 and the cam button 18 properly positioned to prevent disconnection of the wedge 14, and which locking of the wedge 14 will of course have the effect of interlocking the teeth 12 and 13 of the post 10 and head 3 respectively. Following this operation, the upper end of the draw bolt 23 is passed through the strap or straps 2, 2 and the nut 26 tightened, it of course being understood that the head 24 of the bolt engages the machine bed 25. This operation will have the effect of firmly gripping the work between the forward end of the strap and the ma chine bed.

Various changes in the shape, size and arrangement of parts may be made to the form of the invention herein shown and described, without departing from the spirit of the invention or the scope of the claims.

Having now described my invention what I claim and desire to protect by Letters Patent is: y

1. In a self supporting clamp, the combination of a post, a strap, and means adjustably mounting said strap upon said post including a pivot element for permitting transverse movement of said strap upon said post to position the same upon a piece of work.

2. In a device of the character described a clamping strap having its rearward extremity provided with a head, a post rigidly secured to said head, and means for locking the strap down upon the work, the lower extremity of said post being fulcrumed to swing to and from the work.

3. A device for holding work in operative position on a machine bed comprising a rigid elbow fulcrumed at an end on the machine bed, and means for locking the elbow down upon the work.

4. A device of the character described comprising a pair of bars, a head in which the rearward extremities of said bars are fixed for longitudinal adjustment, a support adjustably secured to said head, and means for clamping the bars down upon the work.

5. A device of the character described comprising a pair of bars, a head in which the rearward extremities of said bars are transversely pivoted, a post rigidly secured to said head, and means for clamping said bars down upon the work..

6. In a device of the class described, the combination of a vertical post, a strap, an attaching head having a relatively large aaoam opening therein, and a Wedge member vertically slidable in said head and adapted for abutting engagement with said post to adjustably mount the head in any position upon said post.

7. In a self supporting clamp, the combination of a post, a strap, means for locking said post to. said strap, and means for clamping said strap to a piece of Work.

8. In a device of the class described, the combination of a post, a head adjustably mounted on said post, a plurality of arms independently pivoted in said head, and Work clamping means slidably mounted on said arm to permit independent pivotal movement of said arms with respect to each other.

9. In a self supporting clamp, the combination of a post, a head, means for adjustably locking said head to said post, a strap oscillatively mounted in said head, and means on said strap for clamping the latter to a piece of Work.

10. In a self supporting clamp, the combination of a base, a post sWivelly mounted in said base, a head having a passage therethrough adapted for receiving said post, a Wedge for reciprocably positioning in said passage, for adjustably locking said head to said post, a strap adj ustably pivoted in said head, and adapted to have its free end rest upon said Work, and slidable clamping means positioned upon said strap and engaging said machine bed, for adjustment to securely clamp said strap to hold said Work.

In testimony whereof I have set my hand and seal this 17th da of October, 1919.

CHAR JES (l. ROBERTS. 

